Oil brake device for use in bicycles

Abstract

This disclosure provides an oil brake device for use in the bicycle in which a saddle support is resiliently suspended independent of a main body frame so as to prevent the transmission of shock and vibrations of front and rear wheels in bicycle riding. The brake device is designed to prevent sharp elevation of the saddle support when the bicycle is stopped, or sharp downward movement of the support when starting from the halted position. The device works in cooperation with the wheel brake.

I claim: 
     
       1. An oil brake device for use in bicycles wherein a saddle support is suspended independent of a main body frame, said saddle support having a saddle and a rear wheel driving gear means secured respectively to the upper and the lower ends of said saddle support, said oil brake device comprising an oil cylinder having upper and lower ends with said upper end of said cylinder being adjacent said upper end of said saddle support, a piston rod provided in said cylinder moving together with said saddle support, an oil passage opened at and communicating with the upper and lower ends of the cylinder chamber of said oil cylinder thereby establishing an oil circuit with the oil cylinder chamber, and a main valve located in said oil passage and operated together with a wheel brake to block the flow of oil inside the oil passage by operating the wheel brake and to permit the flow of oil by releasing the brake. 
     
     
       2. An oil brake device for use in bicycles according to claim 1, wherein said oil passage having said main valve is connected to a bypass oil passage having a check valve means, said valve means permitting the flow of oil only in the direction in which said piston rod is allowed to move downward after the flow of oil in said oil passage has been blocked. 
     
     
       3. An oil brake device for use in bicycles according to claim 1, wherein a gate valve means is provided in an intermediate portion of said oil passage opened at and communicating with the upper end of said cylinder chamber of the passage containing said main valve therein, thereby damping the sharp vertical movement of said piston rod. 
     
     
       4. An oil brake device for use in bicycles according to claim 1, wherein an inlet-outlet port opened at and communicating with the upper or lower end of said cylinder chamber of the oil passage containing said main valve therein is gradually reduced in cross section in response to the upward or downward movement of a piston, thereby slowing the speed of said piston before said piston is stopped. 
     
     
       5. An oil brake for use in bicycles according to claim 1, wherein said main valve is fitted with a wire for manipulating the main valve, said wire is connected to a wire for manipulating said wheel brake and a resilient member is interposed between the point of connection and said main valve, whereby, when said wheel brake manipulating wire is manipulated, said main valve is rotated to block the flow of oil in said oil passage and to elastically deform said resilient member after said blockage, and when said wheel brake manipulating wire is released, said main valve is restored to its original position through the elastic restitution of said resilient member.